Fertilizers are important national and agricultural support commodities. Ammonia is a fertilizer itself, but is also used in the form of ammonia nitrate, ammonium sulfate, ammonium carbonate, urea, and other chemical forms in balanced commercial fertilizers. Ammonia is typically produced using natural gas in a process that produces carbon dioxide emissions, which contributes to global warming.
The present process enables the production of ammonia from fossil fuels, typically coal, oil or natural gas, with significantly reduced carbon dioxide release. The present invention co-produces the fertilizer and soil conditioner, polycarbonsuboxide, and permits the production of urea and ammonium carbonate with even greater reduction of carbon dioxide. The combined carbon dioxide releases from the present invention will be far less than the traditional fertilizer production methods using natural gas. Because of the coproducts created in the process, a lower cost for ammonia and fertilizer production results from the process using any fossil fuel feedstock. The largest cost reduction is obtained using a coal feedstock, which reduces costs to about one-ninth of the cost of production using conventional natural gas reforming at current feedstock prices. For this reason, the preferred embodiment uses a coal feedstock and serves as the principle example of the invention in this description.
Polycarbonsuboxide is a polymerized anhydride of malonic acid and acts as a high value organic fertilizer and soil conditioner. Polycarbonsuboxide in most soil produces humic acid. Humic acid is well known to condition soil by aiding in micronutrient ion transport, improving water penetration and retention and disaggregating clay structures.
The advanced coal to coproduct polycarbonsuboxide process has more than double (2.3) the energy consumption per ton of ammonia of the base natural gas plant but less than half the carbon dioxide emission and 2 to 4 times more coproduct than the carbon coproduct in the natural gas cracking process. If added process steps for production of urea or ammonium carbonate, carbon dioxide can be practically eliminated.